Portugal kept alive their chances of qualifying directly for the World Cup when Andre Silva's goal gave them a 1-0 win away to Hungary who played for an hour with 10 men in a bruising encounter on Sunday.
Silva headed in from Cristiano Ronaldo's pinpoint cross three minutes after halftime to give Portugal their seventh successive win in Group B, keeping them three points behind Switzerland who won 3-0 in Latvia to maintain their 100 percent record.
Hungary had Tamas Priskin given a straight red card for elbowing Portugal defender Pepe in the 30th minute, one of several nasty challenges in a rough encounter.
Portugal and Switzerland each have one more game to play before meeting in Lisbon in a potential showdown on Oct. 10.
The winners of the nine European groups qualify directly for next year's World Cup in Russia and the best eight teams play off for four more places.